The present invention relates to sunscreen compositions. More particularly, the present invention relates to sunscreen compositions comprising, as a sunscreening agent, a bis(aminobenzoate)ester of certain alkylene diols or polyols, and to a method for protecting against the harmful effects of ultraviolet radiation employing the sunscreen compositions.
It is well known that sunburn is principally due to exposure of the skin to ultraviolet radiation in the 290 nanometer (nm.) to 320 nm. range. Radiation in this region can result in severe erythema, edema, blistering, and other severe damage to the skin. In contrast, at wavelengths greater than about 320 nm. damage to the skin is relatively slight and the wavelengths in the 320 nm. to 400 nm. range are generally regarded as promoting only tanning of the skin (the so-called tanning region).
Various agents have been proposed for use in cosmetic sunscreen preparations intended to protect against the harmful effects of ultraviolet radiation while permitting desired tanning of the skin. Ideally, the sunscreen agent, when topically applied, is capable of absorbing at least a major portion of the incident radiation in the 290-320 nm. range so as to protect against the harmful effects thereof, and is transparent to wavelengths greater than about 320 nm., thereby permitting the desired tanning effects of the longer wavelength radiation. The sunscreen agent is normally incorporated in a dermatologically innocuous carrier so as to provide a cosmetically acceptable and appealing preparation. In general, the carrier permits convenient topical application of the preparation. Included among the compounds proposed for use as sunscreen agents are p-aminobenzoic acid and certain of its esters, N,N-dimethyl-p-aminobenzoic acid esters, p-methoxy cinnamic acid esters, variously substituted benzophenones, e.g., 2-hydroxy-4-methoxybenzophenone and 2,4-dihydroxybenzophenone, and various salicylates such as phenyl salicylate and 2-ethylhexylsalicylate.